Corn is the principal food of the Mexican diet, and the principal crop- planted on 40% of arable land as of 1990. That year it was estimated that two to three million Mexicans grew corn, mostly on small parcels - 65% of 5 acres or less -of often poor quality land. Most farmers produce corn principally to feed their families, and yet about 40% of Mexico's commercial corn is produced by them as well.